Method and means for purifying molten metal



H. C. DRAKE March 14, 1933.

METHOD AND MEANS FOR FURIFYING MOLTEN METAL 2 Sheets-Sheet l Filed Dec. 28, 1929 INVENTOR lfarmzriflmire H. C. DRAKE March 14, 1933.

METHOD AND MEANS FOR PURIFYING MOLTEN METAL Filed Dec. 28, 1929 2 Sheets-Sheet 2 Patented Mar. 14, 1933 UNITED STATES PATENT OFFICE EABCOUB'I. C. DRAKE, OF HEMPSTEAD, NEW YORK, ASSIGNOB, BY HESNE ASSIGN- MEN TS, TO SPEBBY PRODUCTS, D'TC OF BROOKLYN, NEW YORK, A CORPORATION 01' NEW YORK METHOD AN D. MEANS FOR PUBIFYING MOL'IEN MEDAL Application filed. December 2a, 1029. Serial no. 411,102.

This invention relates to a method and means for purifying molten metal, and utilizes the novel rinciple of the repulsive eflfect of two opposlte electro-magnetic fields,

or the attractive effect of two similar magnetic fields for the purpose of separating the slag or other impurities from the pure metal.

It is a further object of my invention to permit of purification of molten metal in the process of directing said metal into the ingots or molds from a. retort or furnace.

It is a further object of my invention to permit of the utilization of direct current or alternating current for the purpose of estab-e lishing the electro-magnetic fields.

Further objects and advantages of this invention will be pointed out in the following detailed description.

In the accompanying drawings,

Fig. 1 is a vertical section through a retort and disclosing one form of my invention.

Fig. 2 is a vertical section taken substantially" on the line 2-2 of Fig. 4.

' Fig. 3 is a side view of the form of invention disclosed in Fig. 4.

Fig. 4 is a section taken substantially on the line 4-4 of Fig. 3.

Fig. 5 is a front elevation, partly sectioned vertically, through a retort as shown in Figs.

lto 4 inclusive, and showing the ducts and ingots fed from said retort.

Fig. 6 is a bottom view of the arrangement of ducts between the retort and ingot.

Fig. 7 is a vertical section through another form of my invention showing the application thereof to a horizontal retort.

Fig. 8 is a view similar to Fig. 4 but showing a different method of establishing the electromagnetic field.

Referring to Figs. 5 and 7 of the drawings, it will be apparent that I have applied my invention to an arrangement including a furnace or retort 10 having an outlet 11 connecting with a plurality of ducts 12 extending in various directions and leading to molds 13 within which the ingots are formed. The

object of my invention is to cause a separation of im urities from the metal prior to the running of said metal out of the retort so that only the purified metal will pass into the duct 11 to be delivered to the molds 13. I have disclosed various forms of my invention for accomplishing this urpose and one form thereof is disclosed in igs. 1 to 4 inclusive.

Referring to Fig. 1, it will be seen that I have made rovision for passing a current from any sultable source, such as a generator (not shown) through the molten metal within the retort 10 by providing electrodes 20-21 at opposite ends thereof. The current passes through the retort in a direction, for example, such as that indicated by the arrow A, and is then led through a conductor 23 in the opposite direction, as indicated by the arrow B. Said conductor forms one branch of a complete turn 24 and said turns may be multiplied by forming a coil so that in each instance the branch of each of said coils, which is adjacent the retort 10, has current passing therethrough in the direction opposite to that of the current through the retort, in this case in the direction of arrow B. It will thus be seen that the'number of lines of force in the magnetic field immediately adjacent the retort 10 may be indefinitely multiplied by increasing the number of ampereturns.

In the form of the invention disclosed in these figures I have preferred to use a small number of turns of large cross section wire or cable 25 whose low resistance permits of a large amperage. In the form disclosed in Fig. 8 I have preferred to utilize a large number of turns of fine wire forming the coil 25 so that while the amperage through each turn is small, the total ampere-turns ma be made the same in this instance as in the ig. 4 form. The strength of the magnetic field immediately adjacent the retort 10 may be further increased by utilizing a core 31 of magnetic material extending through the turns as shown in Figs. 2 to 4 inclusive.

It will thus be-seen that substantially two electromagnetic fields are established by current travelling in opposite directions within the retort and outside the same but immediately adjacent thereto. One field is established by current flowing through the molten material in the retort in the direction of arrow A, and the other field is established outside the retort by the current flowing through the legs 23 of the turns of wire 24 m the direction of arrow B. The effect of such electro-magnetic fields will be a powerful repulsion which will cause the metal to be repelled to the left in Fig. 1 in the direction of arrow C, while the impurities forming the sla will be expelled in the direction of arrow The opposite arrangement could also be employed, that is, wherein the direction of current in the legs 23 of the turns of wire could be in the same direction as that of arrow A, in which case the metal would be strongly attracted in the direction of arrow D, while the slag would be expelled in the direction of arrow G.

In the case where the repulsion effect of current flowing in opposite directions is utilized and the molten metal is repelled in the direction of arrow C, said metal will be drawn off through outlet 11 to be led through the molds 13 to form the ingots. The slag may be drawn ofi' periodically through a duct 35 which is normally closed by a plug 36 until such time as it is desired to run off the collected impurities in the form of sla The invention is applicable also to hor1- zontal furnaces or retorts in the same manner as in the case of the vertical retort. Thus, in Fig. 7, it will be seen that current is led into the horizontal retort 10' by electrodes 20 -21, and the current is then conducted in -the opposite direction along the retort 10' through the legs 23 of coils of wire 24'. In this case the duct 11 opens downwardly to allow the purified molten metal to be discharged into the mold 13 while the duct 35' leads from a point near the top of the retort 10', as shown in Figs. 7 and 8.

It will be apparent that the above forms of the invention will operate equally well on alternating current as on direct current, because the changes in polarity of the current within the molten metal and in the conductors I adjacent thereto occur simultaneously in both of them. leaving them in the exact relative positions as before, that is to say, if there was repulsion between the metal and adjacent conductors while the sign of the alternating current is, for example, positive, this repulsion will remain when the sign turns to negative, because the current within .the molten metals and the conductors adjacent thereto change simultaneously.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation of my invention, to-

gether with the apparatus which I now con- 1. A method of purifying molten metal which consists in passin current therethrough along a iven axis to establish an electro-magnetic old and passing current through a conductor along an axis substantially parallel to said first axis and adjacent thereto to produce attraction or repulsion of said metal.

2. A method of purifying molten metal which consists in passing current successively through said metal along a given axis thereof and through a conductor substantially parallel to said axis and adjacent thereto so that the electro-magnetic fields thus established interact to produce attraction or repulsion of said metal.

3. In a device for purifying molten metal, a container for the metal, means for passing current through said metal along a given axis to establish an electro-magnetic field, a conductor substantially parallel to said axis, and means for passing current through said conductor to establish a second electro-magnetic field, said conductor being positioned adjacent said first field to produce attraction or repulsion of said metal.

4. In a device for purifying molten metal, a container for the metal, a conductor adjacent said container, a source of current, and means for passing current from said source successively through said metal along a given axis thereof and through said conductor, said conductor being substantially parallel to said axis whereby the interacting electromagnetic fields produce attraction or repulsion of saidmetal.

5. In a device for purifying molten metal, a container for the metal, a conducter adjacent one portion of said container, a source of current, and means for passing current from said source successively through said metal along a given axis thereof and through said conductor. said conductor being substantiallv parallel to said axis whereby the interacting electro-magnetic fields produce attraction or repulsion of said metal.

6. In a device for purifying molten metal, a container for the metal, a conductor, and

signature.

HARCOURT C. DRAKE. 

